Database sizes are growing exponentially and as a result, column-oriented relational databases are being considered as a way to improve the query speed of large data sets, which may also be referred to as catalogues. The rapid development of multi-core central processing units (CPUs) may provide opportunities to further reduce execution time of queries. Improving the parallelism usage of CPUs with large data sets becomes an important issue for column-oriented relational database to speed up the queries. Piece partition strategy may be an efficient means to divide tables of column based databases into numbers of pieces so that multi-core CPUs can work in parallel on these pieces. A piece partition strategy may maximize the utilization of multi-CPU resources.